EARLY BACKGROUND ADAPTATION IN THE MEDAKA Oryzias latipes

PAULA G. VISSIO; MARÍA P. DI YORIO; DANIELA I. PÉREZ SIRKIN; TOMAS H. DELGADIN; JUAN I. FERNANDINO; CLARA SACKS

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Background colour adaptation is both an endocrine and a physiological response to the surrounding environment that many vertebrates are able to display owing to changes in specialized cells called chromatophores present in the skin. However, it is not known if such a process of adaptation may take place during early developmental stages and how they can influence other aspects of development such as growth. The aim of this work was to evaluate if background color adaptation occurs during early developmental stages in the medaka and its possible effects on growth. Thus, we analyzed the number of melanophores, a type of chromatophore, in the head, from medakas adapted to 18, 21, 25, 40 and 60 days post fertilization (dpf) to white or black background. To do this, medaka eggs were taken from 2 to 3 spawnings of different male and females medaka pairs for each timepoint and randomly assigned to black or white backgrounds, reared in Petri dish until hatching and then transferred to tanks of the same background till sampling. Additionally, total length and bodyweight were registered. Data were analyzed by two way ANOVA followed by post hoc comparison. P-values were corrected to avoid type I error. Black adapted medaka larvae presented more head melanophores than white adapted ones (p=0.0001). This difference is not present at 18dpf (p=0.118) but begins at 21dpf (p=0.0292) and increases at 25dpf (p